1. Field of the Invention
This invention relates to a re-usable support structure for a pole, post, mast or other elongate member; the basis of which is a reversibly lockable ground anchor to be inserted in the ground or other substrate.
2. Description of the Related Art
A wide variety of activities depend on the temporary placement of poles in the ground or in a flat floor, road or other substrate, to serve a purpose for a defined period and then to be removed until needed again. Applications include road signs and traffic control measures, advertising or information signs, fences for animal control or crowd control, posts for use when playing sports, tent poles, Christmas tree supports, poles/posts for carrying utility wires, and the like. The invention is more particularly applicable to those activities that require repeated placement, removal, and replacement of poles in or near the same place and where in the absence of the pole the area should be free of obstruction.
Past solutions to this need include: providing posts with heavy laterally spread-out bases that sit upon the ground, forcing posts into the ground so that they are held by friction against the ground around the lowest part of the post, embedding posts into concrete, ice, or some other material which can set around the base of the post, and/or making use of mechanical gripping devices such as keys, wedges, or collets.
Despite the existence of prior art using collet/wedge devices for magnifying a gripping action, there are disadvantages such as the use of a separate tightening collar to be placed around the pole, and operating along a helical screw thread (Partee) and the need in many cases for a part of the anchoring system which remains projecting from the ground even when the pole is not installed.
The inventors were surprised to learn that some expensive, stainless-steel pole assemblies such as flagpoles are sold yet no corresponding system for repeated removal and replacement is offered, apart from sawing off that part of the pole extending from the ground and leaving the remainder embedded in the concrete base.
The problem to be solved could be summarized as being to devise a simple but effective pole-retaining apparatus capable of allowing the pole to be removed and replaced from time to time, and in addition, having minimal impact on an area when the pole is not in place.
A survey of prior art reveals that many sockets to hold poles, such as basketball goal support poles or sign holders, have been described, and many of those include some form of taper lock or collet.
Few if any provide a sound support and/or teach particular insertion or removal tools so that removal is (a) limited to those authorized to do so, and (b) can be carried out reliably and without damage when required. U.S. Pat. No. 5,571,229 to Fitzsimmons et al (dated 1996), (also U.S. Pat. No. 5,752,349) teach an embedded shell, a collet, and use of tapers. In this case, the shell around which the concrete or earth is to be molded is supplied in two halves which are locked together before insertion under the ground surface. The resulting shell plus cap has a rectangular profile in vertical section, except for an inwardly tapered lower end and an inwardly tapered upper opening, comprising a nylon, internally threaded cap that closes down over a series of short tabs, forcing them into the post just below where it emerges from the cap. This is in marked contrast to the single-piece shell with apposed full-length collets and locking means of the present invention, as described below. The post must have a round cross-section. If the post moves upward, perhaps because of vibrations inducted by vigorous play or by wind) after being locked in place, the lower restricted area that makes contact between the post and the shell soon comes out of contact. The only tool used to clamp or release the post is hammer and wedge means to tighten or loosen the nylon cap so that it screws up or down.
Riker (U.S. Pat. No. 7,003,919) teaches a straight-pipe shell to go in the ground, usually into concrete, and a tapered collet surrounding a short portion of the post within the upper end of the shell. Again, there is only a short length of the tapered outer surface of the collet in contact with an adjacent straight cylindrical section, even though the resilience of the preferred plastics will encourage a little deformation.
Sofy (U.S. Pat. No. 5,497,972) teaches a support for a Christmas tree in which a one-piece molded skirt with tapered petals serves as a surround of collets to hold a pole within a base. The skirt co-operates with, when inserted within, a uniformly tapered hole presented to an upper aspect of a base to provide a tapered clamping surround to a cylindrical pole. Screws hold the skirt onto the base and when undone, allow the pole to be removed.